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<head>
  <meta charset="UTF-8">
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  <title>Document</title>
</head>
<body>
  <p>点击按钮获取数组中true元素。</p>
  <button onclick="myFunction()">点我</button>
  <script>
    var arr = [32, 33, 16, 40,true,true,true];
    function checkAdult(arr) {
      return arr === true;
    }
    function myFunction() {
      document.write('true出现了' + arr.filter(checkAdult).length + '次')
    }
  </script>
</body>
</html>